More than a century and a half after Mount Everest was declared the world's tallest peak, its exact height is in dispute.

In 1852, three years after field surveyors had measured the angle of its rise with a 24-inch theodolite, a telescopic instrument used for measuring horizontal and vertical angles, Bengali "computer" Radhanath Sikhdar first calculated the elevation of what was then known as Peak XV. Taking into account "the curvature of the earth, atmospheric refraction and plumb-line deflection," as author Jon Krakauer wrote, Sikhdar set the mountain's altitude at 29,002 feet above sea level.

More recently, Brad Washburn, the American geographer, mountain photographer and climber, produced a map of Everest for the National Geographic Society, giving it a height of 29,035 feet.

Meanwhile, the Chinese, who control the northern approach to the mountain, have started using 29,016 feet.

KATMANDU, Nepal  Sipping black tea on a glacial beach of jagged gray rocks nearly four miles above sea level, the lanky Briton had the air of a jilted lover who didn't want to admit it was over.

Twice before, David Sharp had stood on this gravel plain in Mount Everest's shadow. In 2003 and again in 2004, the 34-year-old engineer had made it well into the "Death Zone" above 26,000 feet before weather, frostbite and lack of oxygen had forced him to turn around, just out of sight of the summit.

Already, the quest had cost Sharp parts of two toes.

Now, warmed by a hissing propane heater in a mess tent at a camp below Everest's forbidding North Face, the bespectacled Briton was telling camp neighbor Dave Watson that his courtship of the mountain was drawing to a close.

Sharp was preparing to begin a new career as a teacher in the fall, and he told the Vermonter that it was time to move on.

"I don't really have the money to come back here anymore," said Sharp, bathed in ghostly blue light filtering through the tent's nylon walls. "So if I don't do it this time, I'm not coming back."

But Sharp didn't believe he'd need to come back. He was sure this third assault would succeed.

He blamed his frostbite on cheap equipment, and believed he'd remedied that. He'd had none of the headaches, diarrhea, coughs or sinus infections that plagued so many at this altitude. He was looking and climbing strong — and was determined, to a fault.

"I would give up more toes — or even fingers to get on top," he told Watson, who was troubled by the comment.

In the summit-at-all-cost world of Mount Everest, both men knew the price can be much higher.

The Nepalese call it Sagarmatha, "goddess of the sky." To Tibetans, it is Qomolungma, "goddess, mother of the world." The British named it Everest, after the head of the Great Trigonometrical Survey of India. Many climbers refer to the mountain simply as "the hill."

Since 1852, when a surveyor's calculations confirmed "Peak XV" as the world's tallest, it has claimed more than 200 lives. Many, like British schoolmaster George Leigh Mallory, who famously declared that he climbed Everest "because it's there," remain on the mountain — frozen reminders that this most hostile of environments was not designed to support life.

It wasn't until 1953, 29 years after Mallory died on his third expedition to Everest, that New Zealander Edmund Hillary and Sherpa Tenzing Norgay reached the summit more than 29,000 feet up. Tales of the feats that earned Hillary a knighthood were like food for generations of British schoolchildren — children like David Sharp.

Growing up in the North Yorkshire market town of Guisborough, the nearest thing to a mountain Sharp had to look up to was the colorfully named, 1,050-foot Roseberry Topping. His passion for climbing blossomed after he entered Nottingham University to pursue an engineering degree, and joined the university's mountaineering club.

Sharp took time off from his job to backpack through South America and Southeast Asia. In 2002, he joined an Irish expedition for his biggest trial yet — Tibet's Cho Oyu, at 26,906 feet the world's sixth-highest peak.

Expedition leader Richard Dougan was amazed at how quickly Sharp acclimated to the thin air. At 5-foot-11 and barely 150 pounds, the sinewy Englishman had no body fat to spare and moved fast to keep warm.

Sharp was clearly a gifted rock climber, free-climbing a particularly tricky rock cliff rather than rely on iffy ropes. Dougan considered him "definitely the strongest member of our team."

He was a convivial camp companion, who would laugh as other climbers tried to eat their frozen chocolate bars, then pull out his stash of fudge, which remained supple even at high altitudes. He enjoyed his whiskey and beer.

After Sharp made it to the top of Cho Oyu with relative ease, Dougan invited him to join a 2003 expedition to Everest.

They would be climbing the North to Northeast Ridge route — the one blazed at such great cost by Mallory.

In the high camps, Mallory entertained his team by reading aloud from Hamlet and King Lear. Nearly 79 years later, Sharp carried a volume of Shakespeare in his battered rucksack while making his first assault on Everest.

Most climbers begin their final ascent in the middle of the night so they arrive at the summit in the early to late morning. This allows maximum daylight hours for making the tricky descent and, not incidentally, for victory photographs.

At around midnight on May 22, 2003, Sharp and Dougan left the 27,231-foot Camp 3 to begin their summit push. Clipping onto a fixed rope by metal jumars, locking ascending devices attached to their safety harnesses, they trudged upward, their boots' spiked crampons biting into the rock and ice.

Everest's summit has only a third as much oxygen as at sea level. There, a climber is more susceptible to frostbite and delirium. Climbers have been known to strip off their clothing in the icy winds, or simply walk off the side of the mountain. Other dangers include fluid on the lungs and high-altitude cerebral edema, or HACE — a sudden, potentially fatal swelling of the brain.

At about 27,760 feet, Sharp and Dougan got a vivid reminder of the mountain's dangers.

They had stopped at a limestone alcove littered with spent oxygen bottles. Inside was a perfectly preserved body, the corpse of an Indian climber who had died in 1996. Climbers had dubbed him "Green Boots," for his distinctive footwear. He lay in the fetal position, facing out.

"He looks like he's sleeping," Dougan remarked to Sharp, who nodded.

They continued their climb, and around 27,900 feet they scaled the first of three nearly vertical rock outcroppings or "steps" that lay between high camp and the summit. As they moved upward, Dougan noticed his friend, normally quicker than average climbers, was slowing down. Just below the Second Step, about 650 vertical feet from the summit, Sharp removed his oxygen mask.

Dougan noticed that Sharp's cheeks and nose had turned an ashen gray. Sharp acknowledged feeling a funny sensation in his fingers and toes.

"David, this is frostbite," Dougan warned.

The summit was tantalizingly close, just two rock climbs away. But the wind was picking up, and Sharp knew he'd reached his limit.

He encouraged Dougan to go on, but they went down together.

En route, the pair came across a Spanish climber who was struggling upward. They offered the man oxygen and verbal encouragement, and stayed until they were sure he was OK.

Back at camp, it soon became clear Sharp would lose most of his left big toe and part of the second toe on his right foot. Sharp bemoaned his decision not to spend $350 for top-of-the-line boots.

"My toes are worth more than $35 apiece," he told expedition member Jamie McGuinness.

The amputations did not stop Sharp. In spite of the pain and disappointment, he was back the next season, ready to try Everest again.

On May 17, 2004, Sharp started out around 12:30 a.m. from his Camp 3, this time solo. After about seven hours of climbing, he got to just below the First Step — even lower than the previous year — when he decided it was too late, and he was too tired to continue.

When he realized the next morning that his fingers were frostbitten, he abandoned the attempt and returned to England.

Sharp took a year off from his adventures to complete a postgraduate course in education. He had secured a job teaching math and was scheduled to start in September.

In this, he was again following the teacher-climber Mallory, whose footsteps would lead him inexorably back to Everest.

Sam's Bar in Katmandu is a hangout where trekkers congregate to write their names on the wall, trade stories on the bamboo-lined terrace and listen to reggae music. As soon as Sharp hit town on March 29 of this year, he headed there to toss back a few beers with McGuinness and discuss his third attempt at Everest.

Again, Sharp was attempting the North Ridge.

Sharp had signed on with Asian Trekking, one of the older companies working the mountain. He would be on the company's International Everest Expedition I, a loose grouping of individuals and smaller teams lumped together for convenience of permitting and accommodations. There were 13 people on Sharp's "team," most making their first assault on Everest.

Sharp had paid Asian Trekking about $6,200 for a bare-bones package. They would carry him into Tibet and up to base camp by truck, then ferry his equipment by yak train to the advance base camp at around 21,000 feet.

Most climbers hire ethnic Sherpas, natives of these high altitudes, to carry gear, prepare food and act as guides. But Sharp's deal called for Asian Trekking to provide tents and food up to the advance base camp.

From there, he was on his own.

McGuinness had asked Sharp to join his expedition, but Sharp declined. He had more than enough cash with him to hire Sherpas, but he wanted to go solo.

Besides, as he'd told his mother Linda before leaving England: "You are never on your own. There are climbers everywhere."

From the north, the approach to Everest passes through a treeless high-desert landscape, what one member of Mallory's third expedition described as "a cheerless, desolate valley suggestive at every turn of the greater desolation to which it leads."

The journey from Katmandu to the Rongbuk Base Camp winds along dusty, gravelly two-lane roads where a boulder is often the only thing standing between the trucks that climbers ride and a thousand-foot plunge. The trip took five days, and sometime on the third, Sharp would have gotten his first glimpse of Everest.

In 1921, Mallory described his first sighting of Everest as it appeared out of the gray mists.

"A preposterous triangular lump rose out of the depths; its edge came leaping up at an angle of about 70 degrees and ended nowhere," he wrote. "Gradually, very gradually, we saw the great mountain sides and glaciers and aretes, now one fragment and now another through the floating rifts, until far higher in the sky than imagination had dared to suggest the white summit of Everest appeared."

At 17,060 feet, the base camp enlivens a barren, 500-yard-wide spoil field with a patchwork quilt of brightly colored tents housing several hundred souls. It's a circus of climbers, lamas, porters, cooks and provisioners, festooned with flapping Buddhist prayer flags of red, yellow, blue, white and green, and perfumed by the aromas of burning juniper boughs, curried lentils, yak-dung fires and open latrines.

Many climbers spend as much as two weeks at the BC to allow their bodies to compensate for the thin air — half the oxygen at sea level — by boosting respiration and even increasing production of oxygen-carrying red blood cells. Quick to acclimate, Sharp stayed only five days before ascending to advance base camp — a two-day, 13-mile trek.

Sharp spent the next few weeks climbing up and down the mountain to acclimatize and to stow tents, oxygen, food and high-altitude fuel to melt snow for water and cook at the higher camps.

He cut a distinctive figure on the mountain with his goatee, his beat-up red and blue rucksack and his red Millet Everest knee boots, the top of the line.

Sharp never told anyone when he was leaving, how high he was going or when he intended to come back. Unlike most climbers, he carried no two-way radio or satellite phone. When he returned from these excursions, instead of using modern designations, he'd talk of reaching "British Camp I" or "British Camp II" — references to the fatal 1924 Mallory expedition.

Death, to Sharp, was merely a biological process. He had told McGuinness that he was an atheist and didn't believe in a higher power, unless it was nature.

Still, he showed respect for Sherpa tradition, and for the "goddess of the sky." Before he left Katmandu, Sharp accepted the cream-colored khata or Buddhist prayer scarf — blessed by a monk or lama and meant to ensure a safe journey to the summit, and back. At ABC, Sharp sat respectfully for the hourlong puja, a ceremony in which a lama blesses the climbers' gear.

And in his tent, beside the Shakespeare volume, was a Bible, the sales sticker from a Katmandu shop still on its cover.

In the first week of May, Sharp began his summit push.

He scaled the North Col, an ice cascade riddled with gaping crevasses, and established a camp at about 25,920 feet, where tents often must be pitched at 45-degree angles. But when he awoke on the third morning, it was snowing and extremely windy, and Sharp decided to abandon the attempt.

When he learned back at camp that, had he gone a little higher, he would have found clearer weather, he second-guessed his decision to turn around.

While plotting his next attempt, Sharp got into a discussion about the use of bottled oxygen with Austrian mountain guide Christian Stangl, a purist who considers climbing with gas a form of "doping." Sharp told Stangl he would only reach for oxygen in an extreme emergency. Stangl suggested it might be better not to tire himself out carrying heavy cylinders he might not use.

As far as Stangl could tell, Sharp was down to just one cylinder. But Sharp knew the mountain was littered with partial bottles that he could use.

By May 11, Sharp had reached Camp One at the North Col again. He popped his head out of his green tent to offer congratulations to Watson and partner Gheorge Dijmarescu as they descended from what was Dijmarescu's eighth successful summit and Watson's second.

Over the next three days, Sharp clawed his way back into the Death Zone, threshold of the summit.

He was at about 27,560 feet shortly after 1 a.m. on the 14th, when Colorado climber Bill Crouse and his team of a dozen clients and Sherpas spotted him on their ascent at a diagonally rising traverse known as the Exit Cracks.

Looking tired, Sharp sat in the falling snow, disconnected from the fixed line to let other, faster climbers pass. In the darkness, the climbers exchanged waves.

Crouse, working as a guide for noted New Zealand climber Russell Brice, reached the summit and keyed his two-way radio as multicolored Buddhist prayer flags flapped in a bitterly cold wind.

"How much time do we have?" Crouse asked Brice, who had been watching the ascent through a telescope from camp at the North Col.

"No more than 20 minutes," the leader said.

Descending, Crouse and his team reached the top of the Third Step, roughly 490 vertical feet from the summit, around 11:20 a.m., when the guide noticed Sharp again at its base — off to the side, out of the blowing wind.

He was clipped to the fixed line, and Crouse's party unclipped and re-clipped to get around him.

"Watch out," Crouse warned Sharp, but nothing else was said.

About an hour and 20 minutes later, at the Second Step, Crouse looked back. The man his team had gone around had moved higher, but barely — just 300 feet or so. He appeared to be the last one up the mountain.

"That guy's going up pretty late in the day today," Crouse said to a companion.

Sharp had already climbed higher than he'd ever been before. At this altitude, he was taking several breaths for each step, but the summit awaited, so close now.

Just a little farther.

Part II: Near top of Everest, he waves off fellow climbers

Down from Everest's summit in the advance base camp, exhausted climbers returned to congratulations, drinks and blessed rest after the day's conquests.

But David Sharp, last spotted hours earlier near the mountain's pinnacle, was not among them that evening, May 14. Still, the experienced climbers who were his friends were not overly concerned.

Dave Watson assumed his friend had crawled into an unoccupied tent at one of the high camps to rest. Sharp had turned around just shy of the summit twice before, so Watson knew the Briton was a smart climber. But he also knew Sharp thought of this as his last trip to Everest and was determined not to leave in defeat.

He remembered a remark Sharp had made several days earlier while acclimatizing at the camp. Other climbers were snapping photos, but he told Watson he was saving the film in his disposable camera.

"I've got all the pictures I need," he'd said, "except for the summit."

Around 11:10 p.m., while many in the camp slept, on the mountain's highest reaches another group began its summit push.

Mark Woodward, a guide for Himalayan Experience, was escorting a camera crew filming fellow New Zealander Mark Inglis' bid to become the first double amputee to reach the summit. Shortly before 1 a.m., at about 27,760 feet, the group reached a rock alcove where Woodward knew they would find "Green Boots" — the frozen Indian climber who'd died there 10 years earlier. Woodward turned to warn a client when he got a shock: There was a second pair of boots protruding from the cave.

In the glare of his headlamp, Woodward could see a man, still clipped onto the red-and-blue guide rope, sitting to the right of the dead Indian, his arms wrapped around his knees. He had no oxygen mask on, and ice crystals had formed on his closed eyelashes.

Cameraman Mark Whetu yelled at him to get moving, but there was no response.

"The poor guy's stuffed," Woodward thought, believing the man was in a hypothermic coma and beyond help.

No one radioed down to expedition leader Russell Brice about a rescue. After pausing just long enough to unclip from the rope, pass Sharp and clip back in, the group trudged on.

About 20 minutes later, a group of Turkish climbers from Middle East Technical University's mountaineering club reached the alcove and also saw Sharp. The group's Sherpa, Lapka, urged the climber to get up and keep moving.

Sharp did not speak, but waved them off.

Others among the three dozen or so climbers attempting the summit that day assumed Sharp was "Green Boots," or didn't notice him at all.

Maxime Chaya had been first up the mountain that day and had passed the notch before the others, but had noticed no one. The beam from his headlamp was weak, and Chaya was focused on his goal of becoming the first Lebanese citizen to summit Everest.

Climbing with a young Sherpa named Dorjee who was also making his first summit attempt, Chaya reached the top at 5:50 a.m., just in time to see the sun rise. At this altitude, you can see the curvature of the Earth, and the light hitting the lesser peaks appeared like an arc of flame.

Chaya stripped off two of his three layers of mittens and gloves for a photo of himself flashing the victory sign, just before his camera froze. The temperature was minus 36 degrees Fahrenheit as he and Dorjee headed back down.

It was a joyous descent until they reached the rock cave around 9:30 a.m. The sun was shining brilliantly, and this time they could not miss Sharp and his red — not green — boots.

Chaya radioed Brice.

Sharp was unconscious and shivering violently, his teeth clenched. His nose had already turned a deep black, his cheeks and lips becoming that way.

He was hatless and without glasses or goggles, wearing just a thin pair of light-blue woolen gloves. (When the Turks had seen Sharp, he was still fully clothed.) Chaya could see his crooked fingers were frozen solid.

Sharp's knees were drawn up in front of him. In Sharp's pack, Chaya found only one oxygen bottle, the gauge on empty.

Chaya told Brice that Sharp's legs appeared to be frozen to the knees, his arms to the elbows. Dorjee had attempted to give the man oxygen, but there was no response.

"There's nothing you can do, Max," Brice said.

Brice reminded Chaya that he had only about 90 minutes' worth of oxygen left. All of his Sherpas were helping clients down the mountain, and there weren't enough people to carry an unconscious man down tricky passes of ice and loose scree.

For nearly an hour, Chaya sat on a rock a few feet from Sharp, crying and pleading into the radio. Down at the ABC, climbers clustered around the radios and wept.

Finally, Chaya and Dorjee got up to leave. Chaya, a Greek Orthodox Christian, stood by the dying man and began reciting the Lord's Prayer in French:

"Notre P Gere qui Fetes aux cieux..."

Finishing, Chaya made the sign of the cross, and he and Dorjee walked away.

***

It is not your body but your mind that carries you to the summit and back, according to one climber who nearly died on Everest.

"Your body is exhausted hours before you reach the top," Beck Weathers wrote in a book recounting an expedition that killed two of the most experienced guides during the 1996 Everest season, the deadliest on record.

Weathers had been left for dead twice and made it down the mountain only because he was able to keep walking.

"It is only through will and focus and drive that you continue to move," wrote the Texas pathologist. "If you lose that focus, your body is a dead, worthless thing beneath you."

As for the dead or dying, Weathers wrote, "you leave them."

When the Turkish team, descending now, encountered Sharp again, it was already in rescue mode: a team member stricken with acute altitude sickness was being evacuated.

Another climber, Eylem Elif Mavis, also descending from the summit, found Sharp in what appeared to be a hypothermic coma. She and her Sherpa, Nima, tried to hook one of their own precious oxygen bottles to Sharp's regulator, but the device did not work.

They scanned the man's clothing for something that might tell them which expedition he was with, hoping they could alert his team to mount a rescue, but found nothing. After a team leader radioed the ABC with the unidentified climber's condition and location, the group moved on.

Phurba Tashi, Brice's chief Sherpa, was descending with some others at 11:45 a.m. and was wearing a video camera on his helmet. Bending toward the shivering man, he asked his name. Whether because of the rising temperature or the oxygen Dorjee had given him, Sharp was somehow able to respond.

"My name is David Sharp," he said, according to some accounts. "I'm with Asian Trekking, and I just want to sleep."

The Sherpas administered oxygen and tried to get Sharp to his feet, but he kept collapsing.

They shifted Sharp a few feet into the sun, then headed down the mountain.

***

Back at the advance base camp, uncertainty about three unaccounted-for climbers was causing a buzz. Besides Sharp, a Malaysian and an American, both first-timers, were overdue.

Many in the camp were less concerned about the experienced Sharp, as they put out calls describing the other two (who would later return safely).

As for Sharp himself, Phurba had not radioed his words down to Brice, and Chaya had suggested the climber he'd found was Russian, not British.

On the morning of May 16, as confusion gave way to serious concern, Phurba described the stricken climber's gear to Watson, who then went to Sharp's yellow tent and retrieved his friend's passport. Yes, the Sherpa confirmed, that was the man he'd seen.

But no new distress call was raised. There was no need.

A Sherpa who had just summitted with a Korean team called in the news from the mountainside: The climber in red boots was dead.

Did David Sharp have to die?

Nearly two weeks after Sharp's death, Australian climber Lincoln Hall was rescued from even higher on the mountain after being left for dead and spending a night exposed to the elements. It took more than a dozen Sherpas and 50 cylinders of oxygen, but Hall — like Weathers — walked down under his own steam.

Edmund Hillary was outraged after hearing that some climbers reported Sharp's condition during the ascent, but were told to continue to the summit. Suggesting he would have aborted his own historic climb to aid the young Briton, Hillary declared that human life was "far more important than just getting to the top of a mountain."

Brice, who has initiated or taken part in 15 Everest rescue missions, insists he didn't know about Sharp's predicament until Sharp was already beyond rescue. He says his radio logs and transcripts of his conversations reveal no calls about a stricken climber on the May 14-15 ascent.

Inglis, who reached the summit on his prosthetic legs, had said in a May broadcast interview that his team radioed to Brice about a stricken climber on their ascent — before Sharp had spent a second night in the cruel temperatures — and was told to go on. But the New Zealander told the AP this month that he was so focused on the challenges of the climb that "I may be mistaken."

Eleven climbers perished on Everest this season, the second worst after 1996. But because of reports that as many as 40 people passed him as he lay dying, Sharp's death has received the most attention.

Questions and recriminations swirl like the plume of snow blowing from Everest's peak:

Why did no one try to administer high-altitude drugs — which most climbing teams carry with them — to stimulate Sharp's breathing and relieve possible brain swelling? Could a couple of hours of high-flow oxygen have revived Sharp enough to get him moving? Why do people who passed Sharp within minutes of each other have significantly different recollections of his condition?

Watson said Sharp was just an hour's climb above the high camps for a strong Sherpa. He would have gladly helped pay for a rescue effort as he and Dijmarescu had done in 2004, saving a Mexican climber.

"It's too bad that none of the people who cared about David knew he was in trouble," Watson said, "because the outcome would have been a lot different."

Chaya, who did as much as anyone to help Sharp, offered condolences to Sharp's parents. But he said Sharp made grave errors by going alone with so little oxygen, without a radio and so late in the day.

"It almost looks," he said, "like he had a death wish."

Although Sharp was not a client, Brice took it upon himself to phone the Englishman's parents with the terrible news. In early June, he hand-delivered his effects to their home in Yorkshire.

Sharp's mother, Linda, did not blame Brice, Chaya or anyone else for her son's death. She thanked them for what they did do.

"Your only responsibility," she said, "is to save yourself — not to try to save anyone else."

***

Nine days after confirmation of Sharp's death, Christian Stangl, the Austrian climber who had befriended him, reached the spot where Sharp's body lay.

Someone had placed Sharp's red and blue rucksack on his chest, to cover his face. Stangl moved the pack, to see for himself if it was indeed Sharp — his eyes half open, his frozen hands at his sides, palms heavenward.

The Austrian replaced the pack, stepped over those red Millet boots and continued to the summit.

Did Sharp himself reach the summit, as some media outlets have speculated? In the one interview they have granted, his parents said they believe he did.

But, as with Everest pioneer George Leigh Mallory, no one is sure.

Sharp left no token at the top. No one has reported seeing him there. His camera, like Mallory's, is unaccounted for.

Jamie McGuinness, who accompanied Sharp on his first Everest climb, wants to believe his friend made it. Regardless, he thinks Sharp would be satisfied to know that, in a kind of frozen afterlife, his body will serve as a guidepost to the summit.

Another reminder of the price some pay for a chance to stand on the roof of the world.

AP National Writer Allen G. Breed reported from the United States and Katmandu Correspondent Binaj Gurubacharya from Nepal. Also contributing to this report were AP writers Ray Lilley in Wellington, New Zealand, and Veronika Oleksyn in Vienna.

Copyright 2007 The Associated Press. All rights reserved. This
material may not be published, broadcast, rewritten or redistributed.

The Second Steps, a rock outcropping above the North Ridge of Mount Everest. British climber David Sharp made it to the bottom of the Second Step in 2003 before frostbite and lack of oxygen forced him to turn around.